This past year, we have focused on the factors regulating anterior mesoderm specification and bodywall muscle development. Capitalizing on the defined cell lineage of C. elegans, we have defined a hierarchy of transcription factors involved regulating muscle development at the single cell level. This has allowed us to tease apart multiple pathways all leading to the eventual activation of HLH-1/MyoD and UNC-120/SRF, the common set of drivers for bodywall muscle fate specification and differentiation. Our results also revealed an unexpected evolutionary conservation of pathway components with anterior muscle development in vertebrates. In collaboration with Drs. Kostrouchova and Kostrouch (Charles University, Prague) we have identified a protein in C. elegans that is related to Mediator Complex subunit 28, a core transcripitonal regualtor that is conserved in all animals. Previous bioinformatic analyses had mis-identified the MED-28 homolog in C. elegans. The study completed this year identified a novel gene as the most likely Med-28 homolog and demonstrated that loss of of its activity results in several developmental defects.